/Engine/Plugins/Editor/ContentBrowser/ContentBrowserAliasDataSoure/Source/ContentBrowserAliasDataSource/Public/ContentBrowserAliasDataSource.h
Legacy functions seem necessary for FrontendFilters to work.
virtual bool Legacy_TryGetPackagePath ( const [FContentBrowserItemData](API\Editor\ContentBrowserData\FContentBrowserItemData) & InItem, [FName](API\Runtime\Core\UObject\FName) & OutPackagePath )